Calibration and validation of a MCC/IMS prototype for exhaled propofol online measurement.

Propofol is a commonly used intravenous general anesthetic. Multi-capillary column (MCC) coupled Ion-mobility spectrometry (IMS) can be used to quantify exhaled propofol, and thus estimate plasma drug concentration. Here, we present results of the calibration and analytical validation of a MCC/IMS pre-market prototype for propofol quantification in exhaled air. Calibration with a reference gas generator yielded an R≥0.99 with a linear array for the calibration curve from 0 to 20 ppb. The limit of quantification was 0.3 ppb and the limit of detection was 0.1 ppb. The device is able to distinguish concentration differences >0.5 ppb for the concentration range between 2 and 4 ppb and >0.9 ppb for the range between 28 and 30 ppb. The imprecision at 20 ppb is 11.3% whereas it is 3.5% at a concentration of 40 ppb. The carry-over duration is 3min. The MCC/IMS we tested provided online quantification of gaseous propofol over the clinically relevant range at measurement frequencies of one measurement each minute.